Human breast and prostate cancer continue to be major health problems today. Few significant inroads have been made on the death rates from these diseases using current diagnostic and therapeutic strategies. With the explosion of new information generated from research on the molecular, biochemical and cellular aspects of growth regulation in eukaryotic cells, significant insights have now been developed into the pathogenesis of these two malignancies. Genetic alterations involving critical growth factors, growth factor receptors, signal transduction pathways, transcription factors, cell cycle regulatory genes and tumor suppressor genes have been now shown to play important roles in various aspects of the malignant process in these diseases. In addition, knowledge regarding the role of non-malignant tissues such as vascular endothelial and immune cells play in the body's response to cancer have opened new avenues for cancer therapeutics directed at cells other than those that are malignant. This Keystone Symposium will be designed to integrate recent knowledge on the basic biology of human breast and prostate cancer with the development and testing of new experimental therapeutics. A laboratory to bedside theme will be developed and carried through the entire meeting with presentation and discussion of the most current basic research on the control of cell growth interfaced with results from testing new molecular therapeutic strategies based on this information. The topics of discussion will include strategies involving direct inhibition of molecules in growth regulatory pathways, introduction of normal genes through gene therapy to replace deleted or altered loci critical to growth regulation, approaches designed to generate host immune responses to tumor specific molecules through new vaccine development, trials directed at inhibition of angiogenesis in malignant tissues and prevention approaches based on recent knowledge regarding steroid hormone/receptor action and retinoid receptors in cell differentiation. We will highlight the exciting and very real area of active translational research, moving basic science information into new therapeutic approaches against breast and prostate cancer.